1. Technical Field
This disclosure relates to an information reproducing apparatus and method, and more particularly, to an information reproducing apparatus and method for reproducing AV (audio Visual) data recorded on an information recording medium rotationally driven, such as a CD-ROM disc, a CD-R disc or a CD-RW disc.
2. Description of the Related Art
An effort has been made to improve the read rate of an information reproducing apparatus that reads information from an information medium rotated, such as a CD-ROM disc, CD-R disc or a CD-RW disc. On the other hand, such an information reproducing apparatus has problems to be resolved, such as noise because of high-speed rotation of the disc and power consumption.
For example, as the data read rate goes up, noise caused by vibration due to rotation and power consumption become more conspicuous at the time of reproducing AV data recorded on a music CD (CD-RA), a video CD or CD as a WAV file or MP3 file through USB speakers installed in a computer. The WAV file is a most popular audio file format handled by Windows that is an OS of Microsoft and has an extension “wav”. The MP3 file is the name of a standardized audio compression technique and has an extension “mp3”, wherein MP is an abbreviation of MPeg audio layer 3.
There is an increased possibility that data may be erroneously read more frequently due to crack or dusk as the disc rotates faster.
However, generally, AV data recorded on a disc such as music data, video data and WAV data, is reproduced at an average transfer rate approximately equal to a single multiple. MP data is reproduced at an average transfer rate approximately equal to one tenth of that for AV data. That is, it takes a much longer time to read AV data and MP data than ordinary data. This does not need to rotate the disc fast.
An improved information reproducing apparatus directed to resolving the above problems has been proposed. In the improved apparatus, data that does not need an error correction mechanism, such as music CDs and some video CDs, is read at a given lowered reproduction rate. However, since the reproduction rate is lowered unconditionally, data cannot be read fast in data ripping or a similar situation required to read data fast. An error correction function is added to WAV data and MP3 data, which will be subject to high-rate read operation in the above-mentioned proposal. Thus, WAV data and MP3 cannot be read at the given lowered reproduction rate.
Japanese Unexamined Laid-Open Publication No. 2000-132901 proposes a disc apparatus capable of controlling the read rate. The proposal shown in this publication analyzes a disc revolution corresponding to the transfer rate of a file to be read, more specifically, the type of data (such as type of file and file size), and thus determines the optimal read rate. The proposal avoids necessity of a requirement for always reading data at the maximum rate, and is therefore preferable in terms of read rate, vibration/noise and power consumption when totally viewed.
However, the technique disclosed in the above publication does not satisfy a request such that the same file is read at different reproduction rates because the unique disc revolution (read rate) is automatically defined based on the type of data to be read (type of file or file size). For example, the proposed technique does not meet different requests for reading data of the same WAV file (for example, WAV reproduction and data ripping).